Wireless charging technology enables it to supply and receive power wirelessly without using a connector to transfer the power. Examples of the wireless charging technology include an electromagnetic induction method using a coil, a wireless power transmission method of transmitting electric energy by transforming the electric energy into a microwave, a resonance method, etc.
For wireless charging, when a device to be wirelessly charged with power is sensed, a wireless power transmitting side transmits and supplies power to the device and determines whether the device needs to be wirelessly charged. When it is determined that the device needs to be wirelessly charged, a power transmission negotiation is conducted and the device which wirelessly receives the power starts being charged.
In this case, since high voltage and high current are used for wireless power transmission, a disconnection or a short circuit may occur in a coil due to a factor, e.g., heat generated for a long time, temperature, corrosion, vibration, shocks, impurities such as dust. When power is continuously supplied to wirelessly transmit the power in a state in which the disconnection or the short circuit occurs in the coil, the power is not transmitted normally and problems such as fire, inner circuit damage, electric shock, etc. may occur.
The wireless charging technology has been currently used in the fields of household appliances, mobile industry, vehicle charging, etc., and is expected to be applied later in the fields of vessels and airplanes. However, a problem as described above may occur when a method of effectively detecting a disconnection or a short circuit occurring in a coil which is a key component of the wireless charging technology is not implemented in a wireless charging system.